The present invention relates to an air bag cover which includes a tear seam in a hidden or non-exposed location.
Overall automobile safety has increased due to the installation of air bag systems in passenger cars. Typically, the air bag system is comprised of an inflator, canister, air bag, and an air bag cover or deployment door. When the inflator is actuated by the impact of an automobile accident, the canister directs the fluid flow from the inflator to the air bag. As the inflator fluid enters the air bag, the air bag extends outward forcing itself towards the deployment door. In turn, the air bag forces the deployment door open and moves the door pivotally away from the emerging air bag which instantly expands into the passenger compartment. The fully inflated air bag cushions the impact felt by an automobile occupant involved in an accident.
The focus of this invention is on the deployment door used on the passenger side of an automobile. Deployment doors have been fastened directly to the reaction canister as part of the air bag system. The deployment door has also been fastened to the vehicle dashboard as well as the air bag canister. Many deployment doors have a tear seam in an exposed or appearance-finish area of the door, sometimes called a class A surface. The tear seams rupture upon the application of force. Once such tear seams rupture, the deployment door moves pivotally away from the emerging air bag. Thus, tear seams used in connection with pivotable deployment doors have been generally known in the prior art.
U.S. Pat. No. 5,897,134 granted to Stein et al. on Apr. 27, 1999 discloses a deployment door which is notched in order to facilitate deployment. The notch is on the inner side surface of the door having class A exterior appearance surface. The notch ruptures upon the influence of an inflating air bag.
U.S. Pat. No. 5,662,351 granted to Phillion et al. on Sep. 2, 1997 discloses a deployment door with an integral flange system. The flange system is comprised of an upper and lower flange which are attached to the air bag system. The lower flange contains a longitudinally grooved portion which is thinner than the rest of the lower flange. When the stress reaches the predetermined elevated level, the grooved portion ruptures fully along it entire length, thus severing its connection with the deployment door. At this point, the deployment door swings open.
U.S. Pat. No. 5,738,366 granted to Phillion on Apr. 14, 1998 discloses a deployment door with a flange projecting from the door. The flange is bolted to a chute structure which is bolted to the air bag system. The chute structure is comprised of a plurality of chute panels and adjacent panels are joined together along fold lines. The force associated with air bag expansion ruptures the fold lines, thus allowing the inflated air bag to push the deployment door open.
U.S. Pat. No. 5,816,609 granted to Gray et al. on Oct. 6, 1998 discloses a deployment door formed with a separate retainer having a frangible hold-down attachment. The deployment door is mounted to the instrument panel by fastening a metal bracket housed on the instrument panel to the underside of the retainer. The frangible attachment holds down the unhinged end of the deployment door and gives way when the air bag is deployed. The frangible attachment includes an extension flap that extends over the retainer. The flap is fastened to the trim panel through bolts that screw into a bracket integrally connected to the trim panel. The bolts pull through the flap with nominal resistance when the air bag is deployed.
While the above mentioned air bag covers work for their intended purposes, they also suffer from certain disadvantages. The typical air bag cover requires the use of class A surfaces. Class A surfaces are readily visible in the vehicle occupant compartment and require expensive material processing or in-mold laminating. The machining of a class A surface is further complicated by adding or juxtaposing a tear seam to the surface. Tear seams which affect class A surfacing further complicate the manufacturing process, which results in increased costs.
Although tear seams exist which do not affect class A surfacing, these tear seams suffer from structural complexity. U.S. Pat. No. 5,662,351 discloses a deployment door with integral flanges. Since the flanges are rigidly positioned, the number of air bag systems which will fit over the flanges is diminished. U.S. Pat. No. 5,738,366 requires the implementation of a chute structure. The cover taught by U.S. Pat. No. 5,816,609 requires the use of a separate retainer. The disadvantage of structural complexity is manifested through expensive manufacturing costs.
There exists a need to construct an air bag cover with a tear seam which does not further complicate the manufacture of class A surfaces. Additionally, the tear seam needs to decrease the structural complexity inherent in the above mentioned air bag cover arrangements.
An interior trim panel has an air bag cover for supporting an air bag canister and closing an opening in the interior trim panel. The air bag cover is openable when an air bag is deployed from the cannister. The air bag cover has a deployment door panel, an attachment structure and a hinge structure. The deployment door panel has concealable and exposable sides. The attachment structure, which has hinged and bendable bracket portions, is integrally connected to the concealable side of the deployment door. The hinge structure has first and second hinged portions separated and connected by a tear seam. The hinge structure is integrally connected to the concealable side of the deployment door and attached to the interior trim panel. When the air bag deploys, the tear seam separates and the bendable bracket portion bends, thus allowing the air bag to deploy through the opening in the interior trim panel.
Accordingly, an object of the invention is to provide an improved air bag deployment cover that does not require manufacturing a tear seam on an exposed or class A surface. The tear seam is constructed on a hinge structure that is spatially removed from the exposed surface of the deployment cover.
A further object of the invention is to provide an improved air bag deployment cover having a door panel that includes a plastic bracket at one side of the concealable side of the door panel that is adapted for attaching an air bag canister and a plastic hinge at the other side of the concealable side of the door panel that is adapted for attaching the door panel to the interior panel of a vehicle. The bracket is receptive to a broad range of air bag canisters.
Another object of the invention is to provide an improved air bag cover in which manufacture is inexpensive. The construction of the air bag cover does not include machining a tear seam into a class A surface and the cover has an integral bracket on one side to support an air bag canister and an integral hinge on its other side to adapt the cover to the interior panel of a vehicle when the cover is attached to the panel. Therefore, the additional cost of such a process is absent from the manufacture of the disclosed air bag cover.